bug#19113: Generate a ChangeLog file from commit logs

[Eli Zaretskii]

> Date: Wed, 19 Nov 2014 15:57:41 -0800
> From: Paul Eggert <eggert@cs.ucla.edu>
> 
> Attached are two patches to change the Emacs repository so that the 
> distributed 
> ChangeLog file is generated automatically from commit logs, instead of being 
> maintained manually.  The first patch renames every ChangeLog file to 
> ChangeLog.1 (or whatever) to get it out of the way -- that is, all existing 
> ChangeLog files are retained in the repository as before.  The second patch 
> arranges for the new ChangeLog file to be generated automatically from future 
> commit messages.  The idea is that developers should continue to write commit 
> messages in ChangeLog style, so the automatic generation is straightforward, 
> but 
> they needn't record their commit messages in ChangeLog files.  This approach 
> was 
> developed by Jim Meyering is used by several other GNU packages.
> 
> This is a first cut, and no doubt could be improved for Emacs, but I thought 
> I'd 
> start the ball rolling by publishing something that works for me.

What's the plan for preventing the generated ChangeLog file from
becoming too large?  Currently, we roll them over to keep the file
below 1MB.

I looked at Coreutils.  They started using a generated file in 2008.
Now, after 6 years, the ChangeLog is over 1MB in size.  Emacs's commit
rate is about 12 times higher than that of Coreutils, so we will hit
that mark in about 6 months.  What then?  gitlog-to-changelog doesn't
have provisions for rolling over, and cannot be told to stop at a
given date.